Push-push multipoled circuit breaker



Jan. 26, 1965 E. T. PLATZ 3,167,627

PUSH-PUSH MULTIPOLED CIRCUIT BREAKER Filed Feb. 7, 1961 5 Sheets-Sheet 1 Q 3 3 Q INVENTOR. 5.4 14 000 2 P1472 Jan. 26, 1965 E. T. PLATZ PUSH-PUSH MULTIPOLED CIRCUIT BREAKER 5 Sheets-Sheet 2 Filed Feb. 7, 1961 INVENTOR. EZWOOD T-F1/47] BY 067%: any, 5mm, gins gfamsz/ 1965 E. T. PLATZ 3,167,627

PUSH-PUSH MULTIPOLED CIRCUIT BREAKER Filed Feb. 7, 1961 5 Sheets-Sheet s IN VEN TOR. EL W000 7. PLATZ Jan. 26, 1965 E. T. PLATZ PUSH-PUSH MULTIPOLED CIRCUIT BREAKER 5 Sheets-Sheet 4 Filed Feb. 7, 1961 NNM INVENTOR. EL WOOD 7.'/.47Z

BY 1 0.571904 5 125465,? 91%: {Sir/m drraP/viys E. T. PLATZ PUSH-PUSH MULTIPOLED CIRCUIT BREAKER Jan. 26, 1965 Filed Feb. 7; 1961 5 Sheets-Sheet 5 J m E mm Q E INVENTOR. LWO0D TFZ/ffz United States Patent O 3,167,627 PUSH-PUSH MULTIPOLED CIRCUET BREAKER Elwood T. Platz, Detroit, Mich., assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsyivania Filed Feb. 7, 1961, Ser. No. 87,722 12 Claims. (Cl. 200-116) The instant invention relates to multipole molded case circuit breakers in which each of the poles is provided with its individual contact operating mechanism and in which an automatic tripping impulse in any one phase is effective to cause tripping of all other phases. More particularly, this invention relates to a circuit breaker construction of this type wherein manual operation is achieved by successive operations of the operating handle in the same direction.

In my U.S. Patent 2,385,727, issued September 25, 1945, entitled Switch, there is disclosed a construction for a single-pole circuit breaker wherein successive linear operations of the operating handle in the same direction are effective to open and close cooperating contacts of the circuit breaker. However, this patent does not disclose a construction whereby the automatic tripping of a single pole will be effective to bring about the automatic tripping of one or more associated poles.

The instant invention provides a novel arrangement whereby a handle having linear movement is provided with a member which, upon successive operations of the handle in the same direction, is effective to bring about opening and closing of the circuit breaker cooperating contacts. For example, with the circuit breaker closed, upon movement of the handle in a first direction the member is directed by the movable contact arm to engage and rotate a latch carrying member to release the latch which holds the releasable cradle. After release of the handle for movement in a reverse direction the next stroke thereof in the first direction is effective to reset the cradle. Upon release of the handle it moves in the opposite direction and at a predetermined point in this travel the main spring is permitted to operate the movable contact arm to circuit closed position.

Prior to the handle having reached its predetermined position, the member carried by the handle is positioned so as to restrain the movable contact arm from moving towards circuit closed position. During the period of restraint, the handle is so positioned that it will prevent the releasable cradle from moving to a position which will permit the main spring to operate the movable contact arm to circuit open position.

The member carried by the handle also carries appropriate indicia thereon indicating the On and Off positions of the circuit breaker with this indicia being viewable through a window in the circuit breaker handle. In addition to the visual indication of contact position a braille type indication is also provided. That is, means are included whereby the position of the circuit breaker handle is different for the contact Closed position than it is for the contact Open position.

The construction outlined above is such that a common pole kicker is included. When a plurality of pole units are stacked side by side and the kickers thereof connected by appropriate means, release of the cradle of a tripped pole is effective to rotate the kicker thereof. This causes rotation of the kickers in the other pole units. Rotation of these kickers is eifective to release the cradle latches of the other pole units, thereby bringing about automatic tripping of these units.

Accordingly, a primary object of this invention is to provide a novel construction for a circuit breaker having trip free characteristics wherein the contacts are operated 3,l5?,627 Patented Jan. 26, 1965 into and out of engagement through successive manual operations of the operating handle in the same direction.

Another object is to provide a single-pole circuit breaker of this type which may readily be stacked in a manner such that a tripping impulse produced upon the tripping of any one pole is effective to cause tripping of all poles.

Still another object is to provide a circuit breaker of this type having both visual and braille type provisions for indicating the condition of the cooperating contacts.

A further object is to provide a circuit breaker of this type having trip-free characteristics and in which a single manual manipulation of the operating handle following an automatic tripping operation is effective to reset the mechanism and permit the main spring to operate the con tacts into engagement.

A still further object is to provide a circuit breaker of this type in which a linearly movable handle carries a pivotally mounted member which is positionable to release the cradle latch and is positionable to restrain movement of the contact arm to the closed position until such time as the handle has reached a predetermined position.

These as well as other objects of this invention shall become readily apparent after reading the following description of the accompanying drawings in which:

FIGURES 1-3 are side elevations of a single-pole unit constructed in accordance with the teachings of the instant invention with the housing cover removed to reveal the mechanism elements. In FIGURE 1 the circuit breaker is in the On position, in FIGURE 2 the circuit breaker is in the Oif position, while in FIGURE 3 the circuit breaker handle is shown fully depressed during op eration of the circuit breaker to its On position.

FIGURE 4 is a cross-section taken through line 44 of FIGURE 1.

FIGURE 5 is a plan view of the circuit breaker of FIGURE 1.

FIGURE 6 is a side elevation hand-1e.

FIGURE 6A is a plan view of the handle.

FIGURE 6B is an end view of the handle.

FIGURES 6C and 6D are cross-sections taken through lines 6C-6C and 6D6D, respectively, of FIGURE 6A looking in the directions of the respective arrows.

FIGURE 7 is a side elevation of the indicator trip actuator member.

FIGURES 7A and 7B are plan and end views, respectively, of the member illustrated in FIGURE 7.

FIGURE 8 is an exploded perspective of the elements comprising the contact operating mechanism.

FIGURE 9 is an end view partially sectioned of twopole units stacked side by side and interconnected for simultaneous automatic tripping.

FIGURE 9A is a fragmentary side elevation of another embodiment of this invention in which the operating handle acts directly upon the cradle for resetting thereof.

Now referring to the figures, each circuit breaker pole unit 10 includes a molded housing comprised of a base 11 and a removable cover 12 joined along line 13 and fastened to one another by rivets 14. The current path through pole unit 10 comprises load connector 15, load terminal member 16, current carrying bimetal 17, flexible conductor 18, movable contact arm 19, movable contact 20, stationary contact 21, line terminal member 22 and line terminal connector 23.

Movable contact 20 is mounted to the lower end of contact arm 19. Ears 19a, 1% extending from the sides of contact arm 19 near the upper end thereof are entered into depressions 11a, 12a of housing portions 11, 12, respectively, whereby contact arm 19 is pivotally mounted to housing 11, 12.

One end 31 of main spring 30, which is a tension proof the manual operating ducing member, is secured to contact arm 19 while the other end 32 is secured to releasable cradle 33. Cradle 33 is a somewhat L-shaped member pivoted near one of the free ends thereof to case embossment 34. The other free end 35 of cradle 33 is formed to serve as a latch tip engageable by latch 36. Latch 36 is an offset formed at the lower free end of temperature compensating bimetal 37. The upper end of compensatin 'bimetal 37 is fixedly secured by rivets 38 to tripper 39 with latch 36 extending through the open rectangular window 441 of tripper 39. Temperature compensating bimetal 37 is so arranged that upon heating thereof latch 36 will move to the left with respect to FIGURE 1.

The upper bifurcated end of tripper 39 is provided with outboard extensions 41 entered into depressions of base 11 and cover 12 to pivotally support tripper 39 to housing 11, 12. Torsion spring 42, mounted to base embossment 13, engages base 11 and tripper 39 to bias the latter clockwise to latching position.

The lower end of tripper 39 is provided with an L- shaped offset 46 positioned so as to encompass the lower end of current carrying bimetal 17.

The upper end of bimetal 17 is fixedly secured to load terminal member 16 which, in turn, is secured to housing 11, 12 by screw 47. Current carrying bimetal 17 is so arranged that upon heating thereof the lower free end deflects to the right with respect to FIGURE 1, carrying with it tripper 37 which is caused to move in a counterclockwise direction about its pivots, thereby moving latch 36 to the right. It is noted that a film of insulating material (not shown) is carried by tripper 39 at the portion thereof engaged by bimetal 17 to insulate tripper 351 from birnetal 17.

The free end of adjusting screw d8 engages the upper end of load terminal member 16 for adjusting the position of current-carrying bimetal 17. Adjusting screw 48 is mated with nut 49 mounted within suitable recesses of housing 11, 12.

Current carrying bimetal 17 passes between the lugs of U-shaped electromagnet 511, thereby forming the energizing turn thereof. Tripper 39 serves as armature for magnet :id. When current of sufficient magnitude flows through pole vunit 143, the energization of magnet 59 will be sufiicient to attract tripper 39, causing it to rotate in a counterclockwise direction about its pivots carrying latch as to the right with respect to FIGURE 1, so that it is clear of cradle latch tip 35. This permits spring .311 to rotate cradle 33 in a clockwise direction causing movement'of the upper end of spring 32 to the right with respect to FIGURE 1. When the line of action of spring 31? passes through the bifurcated upper section of contact arm 1% to the right thereof, a snap opening of contacts 211, 21 will occur and the pole unit elements will assume the trip position of FIGURE 2.

Pole unit further includes manual opera-ting handle 3% which is mounted for sliding linear movement to housing 11, 12 by means of handle ears 301, which are disposed within elongated slots 3112 of housing portions 11, 12. Handle 311% carries pawl 39S and trip member 319 pivotally mounted on axle 3116 whose ends are disposed within elongated open ended slots 397 in the internal side walls of handle 3%. Compression spring 3118 bears agm'nst base shoulder 3G9 and axle 3% thereby biasing the latter upwardly with respect to FIGURE 1 and at the same time biasing handle 3% upwardly.

Torsion spring 311 is mounted upon axle 3116 with one end 311a abutting handle surface 360a and the other end 311!) disposed within trip member notch 31%. Spring 311 is loaded so as to bias trip member clockwise with respect to its position of FIGURE 1. At the same time the central looped extension 3110 is positioned as in FIGURE 1 in the path of pawl 305 to prevent the latter from falling down and interfering with main spring 3%.

Pawl 305 includes a notched hook-like portion 313 within which cradle resetting transverse extension 314 is 4 normally disposed. In the Off position of FIGURE 2 this is accomplished through the engagement of trip member extension 325 with pawl surface 305. When handle 300 is moved downwardly from the position of FIGURE 2 to the position of FIGURE 3 pawl 3195 is caused to pivot clockwise about axle 306 forcing cradle extension 314 to the left thereby pivoting cradle 33 counterclockwise about its pivot 34 to raise latch tip 35 above latch 36. With cradle 33 in latched position the line of action of main spring 31) is to the left of contact arm 19 so that contact arm 19 is biased to the left.

When handle 3% is depressed following the disengagemerit of contacts 20, 21 the elements of the contact operating mechanism assume the positions illustrated in FIG- URE 3. At this time the outboard extension 315 of trip member 310 is disposed Within the narrow portion 315 at the bottom of case pocket 317. Further the extension 318 at the upper end of contact arm 19 abuts trip member 310. Thus trip member 310 is positioned to prevent clockwise rotation of contact arm 19 thereby preventing contacts 20, 21 from being operated into engagement.

Upon release of handle 300 it is moved upwardly by return spring 3118. During the upward movement, until such time as handle 30% has nearly reached the raised position of FIGURE 1, pawl 305 and cradle extension 314 are so related [that cradle 33 cannot move sufficiently toward trip position to prevent main spring 30 from operating contacts 21}, 21 into engagement so that unless suitable precautions are taken release of latch 35, 36 would not enable contacts 20, 21 to part. Thus, during this portion of handle movement trip member downward extension 315 in cooperation with pocket portion 316 maintains trip member 311) so positioned that contact arm 19 is prevented from rotating clockwise to circuit closed position. When handle 300 is raised sufficiently so that extension 315 moves out of pocket portion 316 main spring 3d is free to bring about contacts 21), 21 into engagement with a snap action (FIGURE 1).

In the position of FIGURE 1, it is to be noted that trip member 311) has been rotated counterclockwise to the position of FIGURE 2 through the engagement thereof by contact arm extension 313. In this position trip member extension 315 is disposed within the right hand portion 319 of case pocket 317 thereby maintaining handle 3% in a position which is below the position thereof when the circuit breaker is open as in FIGURE 2.

With the circuit breaker in the On position of FIGURE 1 downward movement of handle 3% moves trip member 31% downward. Contact arm 19 is positioned so that the upward extension 318 thereof deflects the lower end 321 of trip member 310 into engagement with tripper lug projection 322. This causes tripper 39 to be rotated counterclockwise moving latch 36 to the right past latch tip 35.

Main spring 31) is then free to rotate cradle 33 clockwise about its pivot 3 At such time as the line of action of spring 30 passes to the right of contact arm 19 the latter willbe pivoted in a counterclockwise direction so as to bring about the disengagement of cooperating contacts 21), 21 with a snap action. As cradle 33 moves to its trip position of FIGURE 2 projection 324 thereof strikes con tact arm 19 with a hammer-like blow thereby assisting the separation of contacts 21), 21 even when welds are present.

Upon subsequent release of handle 3%, return spring 3% moves handle 31111 to its position of FIGURE 2 in which handle 3% extends more outwardly of housing 11, 12 than when the circuit breaker is On. Handle 3% is free to move to this position since spring 311 has biased trip member 310 clockwise against contact arm extension 318 to a position where extension 315 is disposed within the upper extension 325 of housing pocket 317.

In the circuit breaker Off position of FIGURE 2 cradle extension 314 has forced pawl 30'5 to its most clockwise position against the force of spring 311. Trip member 310 is now so positioned that Oif indicia carried by the arcuate portion 327 of trip. member 311 is viewable through handle window it is to be noted that when the circuit breaker is 911, contact arm extension 318 in engagement with trip member 311') positions trip member 310 so that On indicia carried by arcuate section 327 is viewable through handle window 328 to provide a visual indication of the contact position.

In the embodiment of FIGURE 9A, resetting pawl 33% is eliminated and replaced by cam surface 35f carried by handle 350. The construction of handle 3% is otherwise substantially that of handle 3%.

In addition extension 314; formed integrally with cradle 33 is replaced by pin 352 force fitted to cradle 33. The engagement between surface 351 and pin 352 upon a downward stroke of handle 350 following tripping is effective to move cradle 33 to reset position.

Pole unit 10 further includes common pole kicker 6d having reduced circular portions 61, 62 at the sides of a central generally cylindrical portion 63. Circular portions 61, 62 are journaled within circular apertures 64, 65 of housing portions 11, 12, respectively. Kicker 66 includes a radial extension 66 positioned in the path of movement of ear 67 formed integrally with cradle 33. As cradle 33 moves to the tripped position of FIGURE 2, ear 67 thereof engages kicker 60, the latter is rotated in a counterclockwise direction with respect to FIGURE 1, with edge surface 68 of radial extension 6 6 engaging tripper 39 causing a counterclockwise rotation thereof.

As best seen in FIGURE 9, when two-pole units are stacked together for simultaneous operation, a thin connector 70, of generally rectangular cross-section, is utilized to interconnect kickers 50 of adjacent pole units. Connector 70 extends into the open-ended slots in the confronting ends of adjacent pole-unit kickers 6t). Aperture 64 is surrounded by circular case embossment 71 which is received by circular case embossment '72 of adjacent pole-unit, which surrounds aperture 65. The cooperation of embossment 71, '72 facilities the location of adjacent pole units relative to one another.

When one of the pole units is subjected to overload conditions and the cradle 33 thereof is released, this will cause a counterclockwise rotation of the common pole kicker 66 thereof. This rotation will be transmitted through connector 76 to cause counterclockwise rotation of the common pole kickers of the other units. This causes a counterclockwise pivoting of the tripper 39 of the other pole units, moving the latches 36 thereof to clear the associated latch tips 37 and release the cradles 33 of the other pole units to bring about simultaneous tripping thereof. For simultaneous manual operation, a strip 80 of generally U-shaped cross-section is mounted to the operating handles 35% of the pole units being connected. Strip 89 is provided with apertures aligned with handle windows 328.

Thus this invention provides a novel circuit breaker construction in which successive operations of the circuit breaker handle in the same direction are effective to alternately open and close the circuit breaker. The construction is such that single pole units of this type may readily be inter-connected in a manner such that automatic tripping of any phase is effective to cause automatic tripping of all other phases.

In the foregoing, the invention has been described only in connection with preferred embodiments thereof. Many variations and modifications of the principles of the invention within the scope of the description herein are obvious. Accordingly, it is preferred that the invention not be limited by the specific disclosure herein but only by the appending claims.

I claim:

IL A circuit breaker pole unit comprising a pair of cooperating contacts, an arm to which one of said contacts are mounted, a mechanism for operating said arm between a first and a second position wherein said contacts are engaged and disengaged, respectively; said mechanism including a cradle latchable in a reset position, first means biasing said cradle to a tripped position, said first means being operatively connected to said arm for operation thereof to said first position only when said cradle is in said reset position; said first means being operatively connected to said arm for operation thereof to said second position whenever said cradle is in said tripped position; second means manually operable in a first direction to move said cradle to reset position; third means, and additional means mounting said third means to said second means for movement therewith as well as relative thereto; said third means including a portion operatively positioned to prevent said arm from being operated by said first means to said first position until said second means has reached a predetermined position wherein said cradle is free to move to tripped position after said cradle is unlatched.

2. A circuit breaker pole unit comprising a pair of cooper contacts, an arm to which one of said contacts are mounted, a mechanism for operating said arm between a first and a second position wherein said contacts are engaged and disengaged, respectively; said mechanism including a cradle latchabie in a reset position, first means biasing said cradle to a tripped position, said first means being operatively connected to said arm for operation thereof to said first position only when said cradle is in said reset position; said first means being operatively connected to said arm for operation thereof to said second position whenever said cradle is in said tripped position; second means manually operable in a first direction to move said cradle to reset position; third means, and additional means mounting said third means to said second means for movement therewith as well as relative thereto; said third means including a portion operatively positioned to prevent said arm from being operated by said first means to said first position until said second means has reached a predetermined position wherein said cradle is free to move to tripped position after said cradle is unlatched, latch means for maintaining said cradle in reset position, fourth means responsive to predetermined circuit conditions for releasing said latch means, said third means having another portion operatively engageable with said latch, for release thereof, upon operation of saidsecond means in said first direction while said arm is in said first position.

3. A circuit breaker pole unit comprising a pair of cooperating contacts, an arm to which one of said contacts are mounted, a mechanism for operating said arm between a first and a second position wherein said contacts are engaged and disengaged, respectively; said mechanism including a cradle latchable in a reset position, first means biasing said cradle to a tripped position, said first means being operatively connected to said arm for operation thereof to said first position only when said cradle is in said reset position; said first means being operatively connected to said arm for operation thereof to said second position whenever said cradle is in said tripped position; second means manually operable in a first direction to move said cradle to reset position; third means, and additional means mounting said third means to said second means for movement therewith as well as relative thereto; said third means including a portion operatively positioned to prevent said arm from being 0perated by said first means to said first position until said second means has reached a predetermined position wherein said cradle is free to move to tripped position after said cradle is unlatched, latch means for maintaining said cradle in reset position, fourth means responsive to predetermined circuit conditions for releasing said latch means, said third means having another portion operatively engageable with said latch, for release thereof, upon operation of said second means in said first direction while said arm is in said first position; a kicker operable from a third to a fourth position by said mechanism upon operation of said cradle to said tripped position; said kicker when in said fourth position being effective to release said latch means; said kicker being adapted for connection to a kicker of an adjacent pole unit whereby the kickers are operable in unison so that operation of the kicker of a pole unit by the mechanism thereof is effective to release the latch of an adjacent pole unit.

4. A circuit breaker pole unit comprising a pair of cooperating contacts, an arm to which one of said contacts are mounted, a mechanism for operating said arm between a first and a second position wherein said contacts are engaged and disengaged, respectively; said mechanism including a cradle latchable in a reset position, first means biasing said cradle to a tripped position, said first means being operatively connected to said arm for operation thereof to said first position only when said cradle is in said reset position; said first means being operatively connected to said arm for operation thereof to said second position whenever said cradle is in said tripped position; second means biased in a first direction and manually operable in a second direction to move said cradle to reset position; third means, and additional means mounting said third means to said second means for movement therewith as well as relative thereto; said third means including a portion operatively positioned to prevent said arm from being operated by said first means to said first position until said second means reaches a predetermined movement in said first direction.

5. A circuit breaker pole unit comprising a pair of cooperating contacts, an arm to which one of said contacts are mounted, a mechanism for operating said arm between a first and a second position wherein said contacts are engaged and disengaged, respectively; said mechanism including a cradle latchable in a reset position, first means biasing said cradle to a tripped position, said first means being operatively connected to said arm for operation thereof to said first position only when said cradle is in said reset position; said first means being operatively connected to said arm for operation thereof to said second position whenever said cradle is in said tripped position; second means biased in a first direction and manually operable in a second direction to move said cradle to reset position; third means, and additional means mounting said third means to said second means for movement therewith as Well as relative thereto; said third means including a portion operatively positioned to prevent said arm from being operated by said first means to said first position until said second means reaches a predetermined movement in said first direction, latch means for maintaining said cradle in reset position, fourth means responsive to predetermined circuit conditions for releasing said latch means, a subsequent operation of said second means in said second direction while said arm is in said first position being effective to operate another portion of said third means into operative engagement with said latch for release thereof and thereby permit said first means to operate said arm to said first position.

6. A circuit breaker pole unit comprising a pair of cooperating contacts, an arm to which one of said contacts are mounted, a mechanism for operating said arm between a first and a second position wherein said contacts are engaged and disengaged, respectively; said mechanism including a cradle latchable in a reset position, first means biasing said cradle to a tripped position, said first means being operatively connected to said arm for operation thereof to said first position only when said cradle is in said reset position; said first means being operatively connected to said arm for operation thereof to said second position whenever said cradle is in said tripped position; second means manually operable to move said cradle to reset position; third means, and additional means mounting said third means to said second means for movement therewith as Well as relative thereto; said third means including a portion operatively positioned to prevent said arm from being operated by said first means to said first position until said second means has reached a predetermined position wherein said cradle is free to move to tripped position after said cradle is unlatched; said second means including a manually engageable member operable in a first direction against the force of means biasing said second means in a second direction opposite to said first direction; means guiding said manually engageable member for linear movement; said third means comprising a first member pivotally mounted to said manually engageable member.

7. A circuit breaker pole unit comprising a pair of cooperating contacts, an arm to which one of said contacts are mounted, a mechanism for operating said arm between a first and a second position wherein said contacts are engaged and disengaged, respectively; said mechanism including a cradle latchable in a reset position, first means biasing said cradle to a tripped position, said first means being operatively connected to said arm for operation thereof to said first position only when said cradle is in said reset position; said first means being operatively connected to said arm for operation thereof to said second position whenever said cradle is in said tripped position; second means manually operable to move said cradle to reset position; third means, and additional means mounting said third means to said second means for movement therewith as well as relative thereto; said third means including a portion operatively positioned to prevent said arm from being operated by said first means to said first position until said second means has reached a predetermined position wherein said cradle is free to move to tripped position after said cradle is unlatched; said second means including a manually engageable member operable in a first direction against the force of means biasing said second means in a second direction opposite to said first direction; means guiding said manually engageable member for linear movement; said third means comprising a first member pivotaiiy mounted to said manually engageable member; a housing wherein the pole unit elements previously recited are disposed with said manually engageable member protruding externally of said housing through an opening thereof; biasing means mounted to said manually engageable member biasing said first member to a third position when said contacts are disengaged; said arm when in said first position engaging said first member and operating same against its bias to a fourth position.

8. The pole unit set forth in claim 7 also comprising a latch means for maintaining said cradle in reset position, fourth means responsive to predetermined circuit conditions for releasing said latch means.

9. The pole unit set forth in claim 7 in which the first member includes a portion cooperating with an internal formation of said housing to maintain said first member in said third position until said manually engageable member, after having operated said cradle to said reset position, reaches said predetermined position; said first member when maintained in said third position by said internal formation blocking movement of said arm to said first position.

10. The pole unit set forth in claim 9 in which the first member portion and the internal formation cooperate to maintain said manually engageable member in fifth and sixth positions when said manually engageable member is released and said contacts are engaged and disengaged, respectively; said manually engageable member when in said sixth position extending further beyond the confines of said housing than in said fifth position to produce a braille type indication of contact position.

11. A circuit breaker pole unit comprising a pair of cooperating contacts, an arm to which one of said contacts are mounted, a mechanism for operating said arm between a first and a second position wherein said contacts are engaged and disengaged, respectively; said mechanism including a cradle latchable in a reset position, first means biasing said cradle to a tripped position. said first means being operatively connected to said arm for operation thereof to said first position only when said cradle is in said reset position; said first means being operatively connected to said arm' for operation thereof to said second position whenever said cradle is in said tripped position; second means operable to move said cradle to reset position and third means carried by said second means to prevent said arm from being operated by said first means to said first position until said second means has reached a predetermined position wherein said cradle is free to move to tripped position after said cradle is unlatched; said second means comprising a linearly guided member operable in a first direction against the force of means biasing said second means in a second direction opposite to said first direction; said third means comprising a pivotally mounted member carried by said guided member; a housing wherein the pole unit elements previously recited are disposed with said guided member protruding externally of said housing through an opening thereof; biasing means carried by said guided 0 member biasing said pivotally mounted member to a third position when said contacts are disengaged; said arm when in said first position engaging said pivotally mounted member and operating same against its bias to a fourth position; said pivotally mounted member carrying indicia viewable through an aperture in said guided member; different portions of said indicia being viewable for different positions of said pivotally mounted member to indicate contact engagement and disengagement, as the case may be.

12. A circuit breaker as set forth in claim 1 in which there is a pivot means to which said third means is movably mounted, said second means including a pawl also mounted to said pivot means and engageable with said cradle.

References Cited in the file of this patent UNITED STATES PATENTS 2,013,827 Jennings Sept. 10, 1933 2,385,727 Platz Sept. 25, 1945 2,471,837 Platz May 31, 1949 2,503,409 Platz et al. Apr. 11, 1950 2,811,606 Norden Oct. 29, 1957 2,967,917 Cole Jan. 10, 1961 2,996,589 Meyers Aug. 15, 1961 

1. A CIRCUIT BREAKER POLE UNIT COMPRISING A PAIR OF COOPERATING CONTACTS, AN ARM TO WHICH ONE OF SAID CONTACTS ARE MOUNTED, A MECHANISM FOR OPERATING SAID ARMS BETWEEN A FIRST AND A SECOND POSITION WHEREIN SAID CONTACTS ARE ENGAGED AND DISENGAGED, RESPECTIVELY; SAID MECHANISM INCLUDING A CRADLE LATCHABLE IN A RESET POSITION, FIRST MEANS BIASING SAID CRADLE TO A TRIPPED POSITION, SAID FIRST MEANS BEING OPERATIVLEY CONNECTED TO SAID ARM FOR OPERATION THEREOF TO SAID FIRST POSITION ONLY WHEN SAID CRADLE IS IN SAID RESET POSITION; SAID FIRST MEANS BEING OPERATIVELY CONNECTED TO SAID ARM FOR OPERATION THEREOF TO SAID SECOND POSITION WHENEVER SAID CRADLE IS IN SAID TRIPPED POSITION; SECOND MEANS MANUALLY OPERABLE IN A FIRST DIRECTION TO MOVE SAID CRADLE TO RESET POSITION; THIRD MEANS, AND ADDITIONAL MEANS MOUNTING SAID THIRD MEANS TO SAID SECOND MEANS FOR MOVEMENT THEREWITH AS WELL AS RELATIVE THERETO; SAID THIRD MEANS INCLUDIONG A PORTION OPERATIVELY POSITIONED TO PREVENT SAID ARM FROM BEING OPERATED BY SAID FIRST MEANS TO SAID FIRST POSITION UNTIL SAID SECOND MEANS HAS REACHED A PREDETERMINED POSITION WHEREIN SAID CRADLE IS FREE TO MOVE TO TRIPPED POSITION AFTER SAID CRADLE IS UNLATCHED. 